(pig`pen`) v. TO PIG PEN: The action in which two males and two females participate in a sexual transaction of semen. The two couples fuck missionarily with the two females back facing each other; whilst being fucked the two females share a double ended dildo between their anal cavities. A take off on a pig roast.

Scott: Hey Sonya, want to have a pig roast?
Sonya: Make it a Pig Pen and throw Mrs. Blank, and Mr. Anstead in there, then you have a deal.